"Acmatic" refers to something that is sharp and pointed, but there are several synonyms that can be used to describe this same characteristic. One such synonym is "acicular," which means thin and needle-like. Another similar word is "acuminous," which refers to something that is pointed or sharp at the tip. If you're looking for a word to describe something that is both acmatic and shining, you could use "glittering," "gleaming," or "sparkling." For something that is acmatic and rigid or inflexible, you might use "stiff," "rigid," or "unyielding." Overall, there are many words in the English language that can be used to describe the characteristic of being sharp and pointed, each with their own subtle differences in meaning.